The invention relates to therapeutic treatment of the inner ear. Particularly, methods and apparatus are described that may be used in locating and securing the end of a drug-delivery catheter at the round window niche of the inner ear. Specifically the invention relates to an apparatus and methods that employ a miniature threaded screw pump to inflate a balloon that allows a catheter to be secured within the round window niche of the inner ear.
The present invention generally relates to a multi-functional medical apparatus for use in connection with the inner ear wherein the apparatus is capable of (1) delivering therapeutic agents to internal ear (e.g. inner ear) structures; (2) withdrawing fluid materials from the inner ear; (3) causing temperature, pressure and/or volumetric changes in the fluids and fluid chambers of the inner ear; and (4) enabling internal (e.g. inner) ear structures to be electrophysiologically monitored.
See U.S. Pat. Nos. 5,421,818; 5,474,529 and 5,476,446, each titled Multi-Functional Inner Ear Treatment and Diagnostic System, each to Irving K. Arenberg, and U.S. Pat. No. 6,045,528, titled Inner Ear Fluid Transfer and Diagnostic System, to Arenberg et al., all of which are expressly incorporated by reference.
In order to treat various ear disorders, it may often be necessary to deliver therapeutic agents to inner and middle ear tissues in a rapid and efficient manner. For example, a variety of structures have been developed which are capable of delivering/administering therapeutic agents into the external auditory canal of the outer ear. U.S. Pat. No. 4,034,759 to Haerr discloses a hollow, cylindrical tube manufactured of sponge material (e.g. dehydrated cellulose) that is inserted into the external auditory canal of a patient. When liquid medicines are placed in contact with the tube, it correspondingly expands against the walls of the auditory canal. As a result, accidental removal of the tube is prevented. Furthermore, the medicine absorbed by the tube is maintained in contact with the walls of the external auditory canal for treatment purposes. Haerr does not disclose an inflatable balloon used to secure a catheter in the round window niche of the inner ear.
Other absorbent devices for treatment of the auditory canal and related tissue structures are disclosed in U.S. Pat. No. 3,528,419 to Joechle, U.S. Pat. No. 4,159,719 to Haerr, and U.S. Pat. No. 2,642,065 to Negri.
The Negri patent specifically discloses a medicine delivery device with an internally mounted, frangible medicine container which, when broken, releases liquid medicines into an absorbent member. However, the delivery of therapeutic agents in a controlled and effective manner is considerably more difficult with respect to tissue structures of the inner ear (e.g. those portions of the ear contained within the temporal bone which is the most dense bone tissue in the entire human body), particularly because it is difficult to deliver and maintain a drug in contact with the round window of the inner ear. Exemplary inner ear tissue structures of primary importance include but are not limited to the cochlea, the endolymphatic sac/duct, the vestibular labyrinth, and all of the compartments which include these components. Access to the foregoing inner ear tissue regions is typically achieved through the round window membrane, or alternatively through the oval window/stapes footplate, and the annular ligament. The middle ear shall be defined as the physiological air-containing tissue zone behind the tympanic membrane (e.g. the ear drum) and ahead of the inner ear. It should also be noted that access to the inner ear may be accomplished through the endolymphatic sac/endolymphatic duct and the otic capsule.
The foregoing inner ear tissues are of minimal size, and only readily accessible through microsurgical procedures. In order to treat various diseases and conditions associated with these and other inner ear tissues, the delivery of medicines thereto is often of primary importance as previously noted.
One particularly problematic aspect of treatments delivering drugs to the inner ear, particularly via the round window, is the difficulty of effectively placing a delivery catheter against the round window for a prolonged period of time, such as for a day, a week, or a month. This has proved difficult since the expulsion of a drug from the end of the catheter tends to dislodge the catheter from its place against the round window niche, and the drug formulation itself, which may be oily, only serves to undermine the positional stability of the catheter. There is a need for a device that can easily and practically be used to fix in place a catheter against the round window niche so that the catheter may be used to deliver a drug over a protracted period, such as a week or month or more.
Exemplary medicines which are typically used to treat inner ear tissues include but are not limited to urea, mannitol, sorbitol, glycerol, xylocaine, epinephrine, immunoglobulins, sodium chloride, steroids, heparin, hyaluronidase, aminoglycoside antibiotics (streptomycin/gentamycin), and other drugs, biological materials, and pharmaceutical compositions suitable for treating tissues of the human body.
Likewise, treatment of inner ear tissues and/or fluids may involve altering the pressure, volumetric, and temperature characteristics thereof. Specifically (as will be described in greater detail below), a precise balance must be maintained with respect to the pressure of various fluids within the inner ear and its associated compartments. Imbalances in the pressure levels of such fluids can cause various problems, including but not limited to conditions known as endolymphatic hydrops, endolymphatic hypertension, perilymphatic hypertension, and perilymphatic hydrops.
The present invention may be used with any number of specially-designed treatment units are disclosed which are capable of performing a wide variety of therapeutic functions including but not limited to (1) the controlled, repeatable, and sustained delivery of therapeutic agents directly into the inner ear or at selected middleinner ear interface tissues; (2) the measurement of inner ear electrical potentials (evoked or otherwise) using a technique known as xe2x80x9celectrocochleographyxe2x80x9d (hereinafter xe2x80x9cECoGxe2x80x9d) which is described in greater detail below; (3) the alteration of temperature, volume and pressure conditions within the inner ear; and (4) the controlled withdrawal of inner ear fluid materials.
Accordingly, the present invention encompasses methods and apparatus that employ a miniature threaded screw pump to inflate a balloon wherein the balloon is communicably attached at or adjacent to a distal end of a catheter, and represents an advance in the art of inner ear treatment and drug delivery as described in detail below.
Aspects of the present invention includes methods and apparatus that employ a miniature threaded screw pump to inflate a balloon wherein the balloon is communicably attached at or adjacent to a distal end of a catheter. The pump may employ a threaded interface to drive a piston head relative to a pump housing. The catheter is used to deliver fluids to (and from) the inner ear, and the balloon is adapted to hold the catheter securely at the round window niche of the inner ear. The balloon may take any number of forms, from substantially spherical to an ovoid or toroid shape. It may be located coaxially with the distal end of the catheter or in an offset fashion.
Preferably, the balloon is configured to fit within the round window niche of a patient and be secured upon at least partial inflation. However, the overall structure described may be modified for use in other orifices or apertures. A inflation lumen may be provided to inflate the balloon, whereas at least one delivery lumen may be provided to deliver therapeutic agent to a treatment site or to drain fluid from a treatment site.
The present invention has the advantage that it can be easily, cheaply and practically be used to removably fix in place a catheter against the round window niche so that the catheter may be used to deliver a drug over a protracted period, such as several days, or a week or a month or more. The balloon may be inflated using the screw pump to secure the catheter in the round window niche, and, periodically, the amount of inflation may be adjusted to make sure that the catheter remains in place. When treatment is finished, the catheter may simply and gently be removed by deflation of the balloon. The use of a miniature screw pump allows very fine adjustments to the amount of balloon inflation.
Another advantage of the present invention is that the use of the miniature screw pump allows minute and accurate adjustments in inflation and deflation of the balloon, such that the drug delivery apparatus may be properly retained in the ear over a period of time without causing unpredictable or uncomfortably great pressure against the round window niche of the inner ear.
Particularly, the present invention includes at least each of the following variations:
1. An apparatus for delivery of a therapeutic agent to the round window of the inner ear, the apparatus comprising: an inflation lumen having a proximal end and a distal end, and at least one delivery lumen having a proximal end and a distal end, the distal end of the inflation lumen being in fluid communication with an expandable balloon member adapted to fit and be secured within the round window niche of the inner ear, the proximal end of the inflation lumen being in fluid communication with a miniature pump, the distal end of the delivery lumen being positioned to allow delivery of the therapeutic agent to the round window of the inner ear when the balloon is secured within the round window niche.
2. Apparatus described in (1), wherein the miniature pump is a screw pump employing a threaded interface to drive a piston head relative to a pump housing.
3. The apparatus described in (2) wherein the miniature screw pump comprises a piston, a housing and a threaded interface for driving the piston within the housing.
4. The apparatus described in (3) wherein the miniature screw pump has a displacement of between about 0.5 microliters and 100 microliters.
5. The apparatus described in (4) wherein the miniature screw pump has a displacement of between about 1 microliter and 50 microliters.
6. The apparatus described in (5) wherein the miniature screw pump has a displacement of between about 1 microliter and 25 microliters.
7. The apparatus described in (3) wherein the inflation lumen contains a fluid and wherein balloon inflation is accomplished by displacement of the fluid by means of the miniature screw pump.
8. The apparatus described in (7) wherein the fluid is a viscous fluid.
9. The apparatus described in (8) wherein the viscous fluid is selected from the group consisting of: silicone, an oil, a sugar solution and a polymer.
10. A method for delivering a therapeutic agent to the round window of the inner ear, comprising introducing into the ear an apparatus, the apparatus comprising: an inflation lumen having a proximal end and a distal end, and at least one delivery lumen having a proximal end and a distal end, the distal end of the inflation lumen being in fluid communication with an expandable balloon member adapted to fit and be secured within the round window niche of the inner ear, the proximal end of the inflation lumen being in fluid communication with a miniature pump, wherein the inflation lumen contains a fluid and wherein balloon inflation is accomplished by displacement of the fluid by means of the miniature pump, and wherein the distal end of the delivery lumen is positioned to allow delivery of the therapeutic agent to the round window of the inner ear when the balloon is secured within the round window niche, and, by means of the miniature pump, inflating the balloon to secure it within the round window niche of the inner ear, and delivering a therapeutic agent through the catheter the round window of the inner ear.
11. The method as described in (10), wherein the miniature pump comprises a miniature screw pump, wherein said miniature screw pump comprises a piston, a housing and a threaded interface for driving the piston within the housing.
12. The method as described in (11), wherein the miniature screw pump has a displacement of between about 0.5 microliters and 100 microliters.
13. The method as described in (12), wherein the miniature screw pump has a displacement of between about 1 microliter and 50 microliters.
14. The method as described in (13), wherein the miniature screw pump has a displacement of between about 1 microliter and 25 microliters.
15. The method described in (11) wherein the fluid is a viscous fluid.
16. The method described in (15) wherein the viscous fluid is selected from the group consisting of: silicone, an oil, a sugar solution and a polymer.
In addition to the inventive variations just described, it is contemplated that each component, or the components taken together may have further applicability beyond that described. Of course, the devices as well as the methodology described herein form aspects of the present invention.